// Copyright 2011 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_REGEXP_MIPS_REGEXP_MACRO_ASSEMBLER_MIPS_H_
#define V8_REGEXP_MIPS_REGEXP_MACRO_ASSEMBLER_MIPS_H_

#include "src/macro-assembler.h"
#include "src/mips/assembler-mips.h"
#include "src/regexp/regexp-macro-assembler.h"

namespace v8 {
namespace internal {

    class V8_EXPORT_PRIVATE RegExpMacroAssemblerMIPS
        : public NativeRegExpMacroAssembler {
    public:
        RegExpMacroAssemblerMIPS(Isolate* isolate, Zone* zone, Mode mode,
            int registers_to_save);
        virtual ~RegExpMacroAssemblerMIPS();
        virtual int stack_limit_slack();
        virtual void AdvanceCurrentPosition(int by);
        virtual void AdvanceRegister(int reg, int by);
        virtual void Backtrack();
        virtual void Bind(Label* label);
        virtual void CheckAtStart(Label* on_at_start);
        virtual void CheckCharacter(uint32_t c, Label* on_equal);
        virtual void CheckCharacterAfterAnd(uint32_t c,
            uint32_t mask,
            Label* on_equal);
        virtual void CheckCharacterGT(uc16 limit, Label* on_greater);
        virtual void CheckCharacterLT(uc16 limit, Label* on_less);
        // A "greedy loop" is a loop that is both greedy and with a simple
        // body. It has a particularly simple implementation.
        virtual void CheckGreedyLoop(Label* on_tos_equals_current_position);
        virtual void CheckNotAtStart(int cp_offset, Label* on_not_at_start);
        virtual void CheckNotBackReference(int start_reg, bool read_backward,
            Label* on_no_match);
        virtual void CheckNotBackReferenceIgnoreCase(int start_reg,
            bool read_backward, bool unicode,
            Label* on_no_match);
        virtual void CheckNotCharacter(uint32_t c, Label* on_not_equal);
        virtual void CheckNotCharacterAfterAnd(uint32_t c,
            uint32_t mask,
            Label* on_not_equal);
        virtual void CheckNotCharacterAfterMinusAnd(uc16 c,
            uc16 minus,
            uc16 mask,
            Label* on_not_equal);
        virtual void CheckCharacterInRange(uc16 from,
            uc16 to,
            Label* on_in_range);
        virtual void CheckCharacterNotInRange(uc16 from,
            uc16 to,
            Label* on_not_in_range);
        virtual void CheckBitInTable(Handle<ByteArray> table, Label* on_bit_set);

        // Checks whether the given offset from the current position is before
        // the end of the string.
        virtual void CheckPosition(int cp_offset, Label* on_outside_input);
        virtual bool CheckSpecialCharacterClass(uc16 type,
            Label* on_no_match);
        virtual void Fail();
        virtual Handle<HeapObject> GetCode(Handle<String> source);
        virtual void GoTo(Label* label);
        virtual void IfRegisterGE(int reg, int comparand, Label* if_ge);
        virtual void IfRegisterLT(int reg, int comparand, Label* if_lt);
        virtual void IfRegisterEqPos(int reg, Label* if_eq);
        virtual IrregexpImplementation Implementation();
        virtual void LoadCurrentCharacter(int cp_offset,
            Label* on_end_of_input,
            bool check_bounds = true,
            int characters = 1);
        virtual void PopCurrentPosition();
        virtual void PopRegister(int register_index);
        virtual void PushBacktrack(Label* label);
        virtual void PushCurrentPosition();
        virtual void PushRegister(int register_index,
            StackCheckFlag check_stack_limit);
        virtual void ReadCurrentPositionFromRegister(int reg);
        virtual void ReadStackPointerFromRegister(int reg);
        virtual void SetCurrentPositionFromEnd(int by);
        virtual void SetRegister(int register_index, int to);
        virtual bool Succeed();
        virtual void WriteCurrentPositionToRegister(int reg, int cp_offset);
        virtual void ClearRegisters(int reg_from, int reg_to);
        virtual void WriteStackPointerToRegister(int reg);
        virtual bool CanReadUnaligned();

        // Called from RegExp if the stack-guard is triggered.
        // If the code object is relocated, the return address is fixed before
        // returning.
        // {raw_code} is an Address because this is called via ExternalReference.
        static int CheckStackGuardState(Address* return_address, Address raw_code,
            Address re_frame);

    private:
        // Offsets from frame_pointer() of function parameters and stored registers.
        static const int kFramePointer = 0;

        // Above the frame pointer - Stored registers and stack passed parameters.
        // Registers s0 to s7, fp, and ra.
        static const int kStoredRegisters = kFramePointer;
        // Return address (stored from link register, read into pc on return).
        static const int kReturnAddress = kStoredRegisters + 9 * kPointerSize;
        // Stack frame header.
        static const int kStackFrameHeader = kReturnAddress;
        // Stack parameters placed by caller.
        static const int kRegisterOutput = kStackFrameHeader + 20;
        static const int kNumOutputRegisters = kRegisterOutput + kPointerSize;
        static const int kStackHighEnd = kNumOutputRegisters + kPointerSize;
        static const int kDirectCall = kStackHighEnd + kPointerSize;
        static const int kIsolate = kDirectCall + kPointerSize;

        // Below the frame pointer.
        // Register parameters stored by setup code.
        static const int kInputEnd = kFramePointer - kPointerSize;
        static const int kInputStart = kInputEnd - kPointerSize;
        static const int kStartIndex = kInputStart - kPointerSize;
        static const int kInputString = kStartIndex - kPointerSize;
        // When adding local variables remember to push space for them in
        // the frame in GetCode.
        static const int kSuccessfulCaptures = kInputString - kPointerSize;
        static const int kStringStartMinusOne = kSuccessfulCaptures - kPointerSize;
        // First register address. Following registers are below it on the stack.
        static const int kRegisterZero = kStringStartMinusOne - kPointerSize;

        // Initial size of code buffer.
        static const int kRegExpCodeSize = 1024;

        // Load a number of characters at the given offset from the
        // current position, into the current-character register.
        void LoadCurrentCharacterUnchecked(int cp_offset, int character_count);

        // Check whether preemption has been requested.
        void CheckPreemption();

        // Check whether we are exceeding the stack limit on the backtrack stack.
        void CheckStackLimit();

        // Generate a call to CheckStackGuardState.
        void CallCheckStackGuardState(Register scratch);

        // The ebp-relative location of a regexp register.
        MemOperand register_location(int register_index);

        // Register holding the current input position as negative offset from
        // the end of the string.
        inline Register current_input_offset() { return t2; }

        // The register containing the current character after LoadCurrentCharacter.
        inline Register current_character() { return t3; }

        // Register holding address of the end of the input string.
        inline Register end_of_input_address() { return t6; }

        // Register holding the frame address. Local variables, parameters and
        // regexp registers are addressed relative to this.
        inline Register frame_pointer() { return fp; }

        // The register containing the backtrack stack top. Provides a meaningful
        // name to the register.
        inline Register backtrack_stackpointer() { return t4; }

        // Register holding pointer to the current code object.
        inline Register code_pointer() { return t1; }

        // Byte size of chars in the string to match (decided by the Mode argument).
        inline int char_size() { return static_cast<int>(mode_); }

        // Equivalent to a conditional branch to the label, unless the label
        // is nullptr, in which case it is a conditional Backtrack.
        void BranchOrBacktrack(Label* to,
            Condition condition,
            Register rs,
            const Operand& rt);

        // Call and return internally in the generated code in a way that
        // is GC-safe (i.e., doesn't leave absolute code addresses on the stack)
        inline void SafeCall(Label* to,
            Condition cond,
            Register rs,
            const Operand& rt);
        inline void SafeReturn();
        inline void SafeCallTarget(Label* name);

        // Pushes the value of a register on the backtrack stack. Decrements the
        // stack pointer by a word size and stores the register's value there.
        inline void Push(Register source);

        // Pops a value from the backtrack stack. Reads the word at the stack pointer
        // and increments it by a word size.
        inline void Pop(Register target);

        Isolate* isolate() const { return masm_->isolate(); }

        MacroAssembler* masm_;

        // Which mode to generate code for (Latin1 or UC16).
        Mode mode_;

        // One greater than maximal register index actually used.
        int num_registers_;

        // Number of registers to output at the end (the saved registers
        // are always 0..num_saved_registers_-1).
        int num_saved_registers_;

        // Labels used internally.
        Label entry_label_;
        Label start_label_;
        Label success_label_;
        Label backtrack_label_;
        Label exit_label_;
        Label check_preempt_label_;
        Label stack_overflow_label_;
        Label internal_failure_label_;
    };

} // namespace internal
} // namespace v8

#endif // V8_REGEXP_MIPS_REGEXP_MACRO_ASSEMBLER_MIPS_H_
